unknown component

Discussion in 'General Electronics Chat' started by jholman, Apr 11, 2014.

  1. jholman

    Thread Starter New Member

    Apr 11, 2014
    I recently was pulling some components of a used board and ran into what i thought at first was a transistor. Testing with a meter i found a diode junction, but when i tested other lead combinations the diode junction switched to 0 ohms (both directions). After careful study, the diode switches to o ohms until you reverse the probes, then it goes back to being a diode again. Does anyone know what this is? Whatever stated it diode is in, it will not revert until the - probe is touched to the lead.
  2. kubeek

    AAC Fanatic!

    Sep 20, 2005
    It is a mosfet. You can charge the gate capacitance using your probes and then the mosfet will stay on for a while until the gate discharges. It has a parasitic diode between source and drain, so that is what you measure when it is off.
    THE_RB and jholman like this.